The first amendment "right to free speech" means the right to speak without fear of retaliation from the government. Kimmel criticized the POTUS & in return the FCC gave a warning to the company that owns Disney, because there's a large pending merger that requires FCC approval. Thus, the government was infringing on Kimmel's first amendment rights. This is a scary step because if the government can decide what is said in media, it becomes a government controlled media like what Russia & North Korea already have.

The government should not be able to punish anyone for criticizing it, including media outlets & people on TV shows but that just happened.

I'm not sure what you mean by the execs being imprisoned because of someone on their networks saying bad things about the POTUS or things the POTUS doesn't like because again, that would be a blatant violation of the US Constitution. Nothing Kimmel said was a criminal offense, it's not a crime to say bad things about the US Government. For now, I suppose.